require 'openssl'

# This is perhaps the saddest thing I have ever written...
#
# Don't cry for me...I'm already dead.
#
module OpenSSL
  module SSL
    VERIFY_PEER = VERIFY_NONE
  end
end

require 'yaml'
require 'hashlib'
require 'deep_merge'
require 'addressable/uri'
require 'httparty'

module Onering
  class API
    module Actions
      class Retry < ::Exception; end
    end

    module Errors
      class Exception < ::Exception; end
      class NotConnected < Exception; end

      class ClientError < Exception; end
      class Unauthorized < ClientError; end
      class Forbidden < ClientError; end
      class NotFound < ClientError; end

      class ServerError < Exception; end
      class ConnectionTimeout < Exception; end
      class AuthenticationMissing < Exception; end
    end

    include Onering::Util
    include ::HTTParty

    attr_accessor :url
    format        :json

    DEFAULT_CONFIG={}
    DEFAULT_BASE="https://onering"
    DEFAULT_PATH="/api"
    DEFAULT_OPTIONS_FILE=["~/.onering/cli.yml", "/etc/onering/cli.yml"]
    DEFAULT_CLIENT_PEM=["~/.onering/client.pem", "/etc/onering/client.pem"]
    DEFAULT_CLIENT_KEY=["~/.onering/client.key", "/etc/onering/client.key"]
    DEFAULT_VALIDATION_PEM="/etc/onering/validation.pem"


    def initialize(options={})
      @_config = {}
      @_plugins = {}
      @_connection_options = options

    # load and merge all config file sources
      _load_config(@_connection_options[:configfile], @_connection_options.get(:config, {}))

    # set API connectivity details
      Onering::API.base_uri @_config.get(:url, DEFAULT_BASE)

    # add default parameters
      options.get('config.params',{}).each do |k,v|
        _default_param(k,v)
      end

      Onering::Reporter.setup()
      connect(options) if options.get(:autoconnect, true)
    end

    def connect(options={})
    # setup authentication
      _setup_auth()

      return self
    end


    def request(method, endpoint, options={})
      endpoint = [@_config.get(:path, DEFAULT_PATH).strip, endpoint.sub(/^\//,'')].join('/')

      case (method.to_sym rescue method)
      when :post
        rv = Onering::API.post(endpoint, options)
      when :put
        rv = Onering::API.put(endpoint, options)
      when :delete
        rv = Onering::API.delete(endpoint, options)
      when :head
        rv = Onering::API.head(endpoint, options)
      else
        rv = Onering::API.get(endpoint, options)
      end

      if rv.code >= 500
        raise Errors::ServerError.new("HTTP #{rv.code} - #{Onering::Util.http_status(rv.code)} #{rv.parsed_response.get('error.message','') rescue ''}")
      elsif rv.code >= 400
        message = "HTTP #{rv.code} - #{Onering::Util.http_status(rv.code)} #{rv.parsed_response.get('error.message', '') rescue ''}"

        case rv.code
        when 401
          raise Errors::Unauthorized.new(message)
        when 403
          raise Errors::Forbidden.new(message)
        when 404
          raise Errors::NotFound.new(message)
        else
          raise Errors::ClientError.new(message)
        end
      else
        rv
      end
    end


    def get(endpoint, options={})
      request(:get, endpoint, options)
    end

    def post(endpoint, options={}, &block)
      if block_given?
        request(:post, endpoint, options.merge({
          :body => yield
        }))
      else
        request(:post, endpoint, options)
      end
    end

    def put(endpoint, options={}, &block)
      if block_given?
        request(:put, endpoint, options.merge({
          :body => yield
        }))
      else
        request(:put, endpoint, options)
      end
    end

    def delete(endpoint, options={})
      request(:delete, endpoint, options)
    end


  # I'm not a huge fan of what's happening here, but metaprogramming is hard...
  #
  # "Don't let the perfect be the enemy of the good."
  #
    def method_missing(method, *args, &block)
      modname = method.to_s.split('_').map(&:capitalize).join

      if not (plugin = (Onering::API.const_get(modname) rescue nil)).nil?
        @_plugins[method] ||= plugin.new.connect(@_connection_options)
        return @_plugins[method]
      else
        super
      end
    end

    def opt(name, default=nil)
      @_config.get(name, default)
    end


    def status()
      Onering::API.get("/").parsed_response
    end



  private
# -----------------------------------------------------------------------------
    def _load_config(configfile, config={})
      if configfile.nil?
        configfile = []
      else
      # recursively grab all .yml files if directory is specified
        configfile = (File.directory?(configfile) ? Dir.glob(File.join(configfile, "**", "*.yml")).sort : [configfile])
      end

    # list all existing config files from least specific to most
      @_configfiles = (configfile + DEFAULT_OPTIONS_FILE).compact.select{|i|
        (File.exists?(File.expand_path(i)) rescue false)
      }.reverse

    # merge all config files with more-specific values overriding less-specific ones
      @_config = DEFAULT_CONFIG
      @_configfiles.each do |i|
        c = YAML.load(File.read(File.expand_path(i))) rescue {}
        @_config.deep_merge!(c)
      end

    # settings specified in the library override everything
      @_config.deep_merge!(config.compact) unless config.empty?
    end


# -----------------------------------------------------------------------------
    def _setup_auth()
      type = @_config.get('authentication.type', :auto)

      case type.to_sym
      when :token
        _setup_auth_token()

      else
        _setup_auth_ssl()
      end
    end

# -----------------------------------------------------------------------------
    def _default_param(key, value)
      @_default_params ||= {}
      @_default_params[key] = value
      Onering::API.default_params(@_default_params)
    end

# -----------------------------------------------------------------------------
    def _setup_auth_ssl()
      begin
      # get first keyfile found
        key = (([@_config.get('authentication.keyfile')] + DEFAULT_CLIENT_PEM).compact.select{|i|
          (File.exists?(File.expand_path(i)) rescue false)
        }).first

      # SSL client key not found, attempt autoregistration...
        if key.nil?
          if @_config.get('authentication.autoregister', true)
            validation_key = @_config.get('authentication.validation_keyfile', DEFAULT_VALIDATION_PEM)
            validation_key = (File.expand_path(validation_key) rescue validation_key)

          # if validation key exists, autoregister
            if File.size?(validation_key)
            # set the authentication PEM to validation.pem
              Onering::API.pem(File.read(validation_key))

            # attempt to create client.pem from least-specific to most, first writable path wins
              clients = [{
                :path       => "/etc/onering",
                :name       => fact('hardwareid'),
                :keyname    => 'system',
                :autodelete => true
              },{
                :path       => "~/.onering",
                :name       => ENV['USER'],
                :keyname    => 'cli',
                :autodelete => false
              }]

            # for each client attempt...
              clients.each do |client|
              # expand and assemble path
                client[:path] = (File.expand_path(client[:path]) rescue client[:path])
                keyfile = File.join(client[:path], 'client.pem')

              # skip this if we can't write to the parent directory
                next unless File.writable?(client[:path])
                Dir.mkdir(client[:path]) unless File.directory?(client[:path])
                next if File.exists?(keyfile)

              # attempt to create/download the keyfile
                response = self.class.get("/api/users/#{client[:name].strip}/keys/#{client[:keyname]}")

              # if successful, write the file
                if response.code < 400 and response.body
                  File.open(keyfile, 'w').puts(response.body)
                  raise Actions::Retry.new
                else
              # all errors are fatal at this stage
                  raise Errors::ClientError.new("Cannot autoregister client: HTTP #{response.code} - #{(response.parsed_response || {}).get('error.message', 'Unknown error')}")
                end
              end

            # it is an error to not have created a client.pem by now
              raise Errors::AuthenticationMissing.new("Cannot autoregister client: keyfile not created")

            else
            # cannot autoregister without a validation.pem
              raise Errors::AuthenticationMissing.new("Cannot autoregister client: validation keyfile is missing")
            end
          else
            raise Errors::AuthenticationMissing.new("Cannot find SSL key and autoregistration is disabled")
          end
        else
          Onering::API.pem(File.read((File.expand_path(key) rescue key)))
        end

      rescue Actions::Retry
        retry
      end
    end


# -----------------------------------------------------------------------------
    def _setup_auth_token()
    # get first keyfile found
      key = @_config.get('authentication.key')
      raise Errors::AuthenticationMissing.new("Cannot find an API token") if key.nil?

    # set auth mechanism
      Onering::API.headers({
        'X-Auth-Mechanism' => 'token'
      })

    # set default parameters
      _default_param(:token, key)
    end
  end
end